How far back can a company file an overdue CT600?
Short version. An overdue Company Tax Return still needs attention. How far back you can file through a particular service depends on its software scope. SimpleCompanyTax supports periods starting on or after 1 April 2015. That date is a service limit, not a rule cancelling older obligations.
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1. Filing obligation and software scope
When HMRC issues a notice to deliver a return, the company must respond even if it has no tax to pay. The normal filing deadline is 12 months after the accounting period ends. A late return and a return outside a software provider’s date range are different questions.
For a period outside this service, use software or professional help that covers the required return. Check what HMRC is asking for rather than changing old dates to pass a software check.
2. Prepare the earlier return
Use the accounts, period dates and tax adjustments belonging to that earlier period. Do not substitute the current year’s figures. Check whether the accounts and CT600 need the same filing targets.
Follow the company filing guide for the exact setup, Financial data and review steps. Annual subscription guidance explains supported earlier periods and amendments.
3. Long periods and existing returns
An accounts period longer than 12 months normally needs two Company Tax Returns. Review both dates and allocate the amounts that need a customer choice. If the first return is already filed, choose the appropriate remaining-return or amend-first/file-second journey.
Fictional example: accounts cover 1 January 2019 to 30 June 2020. The displayed returns cover 2019 and the six months to 30 June 2020. If one is already filed, do not submit it again as a new return merely to complete the other.
- Long accounts periods and two CT600 returns
- File only the outstanding second CT600
- Amend the first return and file the second
4. Check the result
Review the prepared dates, original or amended status, accounts attachments and tax computation. After filing, check the authority’s final outcome. A saved draft or submission message is not confirmation that HMRC accepted the return.
This is general filing guidance. Take advice if you need help establishing the figures, required returns or consequences of late filing.